Effects of multiple pregnancy following IVF on the functional state of the hemostatic system: new views and hypotheses

Objective. To provide a systematic analytical review on adaptive changes in the hemostatic system in multiple pregnancy following IVF. Materials and methods. Articles were searched in Russian and international databases using the following key words: “ART”, “IVF”, “multiple pregnancy”, “twin pregnancy”, “hemostasis”, “hemostasis in IVF”, “thrombophilia”, “ovulation induction”. Selection was conducted in three stages and included: review of titles and abstracts, screening of potential full texts and reference lists of potential full texts to identify other suitable articles. Suitable articles that were most relevant to clinical practice were considered. Results. High estrogen levels during ovulation induction in ART protocols lead to increased synthesis of procoagulant factors and decreased activity of anticoagulants and fibrinolytic system, which increases the risk of thrombosis. The ADAMTS13/vWF axis plays a special role: decreased ADAMTS13 metalloproteinase activity and increased von Willebrand factor levels lead to the accumulation of ultra-large vWF multimers, increasing the risk of thrombotic thrombocytopenic purpura and other thrombotic complications. Multiple pregnancy following IVF complicate these changes due to even higher estrogen levels proportional to the number of fetuses. Studies show that the risk of venous thrombosis is significantly higher in these patients, especially in the first trimester and for 12 weeks postpartum. Despite this, data on thrombotic complications in multiple pregnancy following IVF are scarce, emphasizing the need for further research. Conclusion. In multiple pregnancy following IVF, the risk of thrombosis is significantly higher due to changes in the hemostatic system. Early detection and monitoring of thrombophilia conditions, especially those related to the ADAMTS13/vWF axis, as well as an individualized approach to prevention and treatment, may reduce maternal and fetal risks. Further research is needed to develop effective strategies for monitoring and preventing thrombotic complications in pregnant women after ART. Key words: multiple pregnancy, twin pregnancy, in vitro fertilization, IVF, assisted reproductive technologies, ART, von Willebrand factor, vWF, ADAMTS-13 metalloproteinase, hemostasis in IVF, fibrinolytic system, ovulation induction